Gas powered heater

ABSTRACT

A gas powered heater ( 1 ) for use in a chafing trolley comprises a support element ( 10 ) defining a hollow interior region ( 12 ) for a disposable fuel gas canister ( 3 ), which is coupled to the support element ( 10 ) by a coupling element ( 15 ). Fuel gas from the fuel gas canister ( 3 ) is delivered through a pipe ( 42 ) to a fuel gas controller ( 17 ) and in turn to a fuel gas burner element ( 18 ). A lever ( 36 ) operates a control valve ( 45 ) in the fuel gas controller ( 17 ) for controlling the supply of fuel gas to the burner ( 18 ). The fuel gas controller is mounted on a mounting platform ( 28 ) and extends downwardly into the hollow interior region ( 12 ) of the support element ( 10 ) and is located offset to one side and spaced apart from the fuel gas canister ( 3 ). The location of the fuel gas controller ( 17 ) and in turn the fuel gas burner element ( 18 ) to one side of the fuel gas canister ( 3 ) permits the overall headroom required by the gas powered heater ( 1 ) to be minimised, so that the gas powered heater ( 1 ) is suitable for use in a chafing trolley.

The present invention relates to a gas powered heater, and in particular, to a gas powered heater for use in a chafing trolley or unit.

Chafing trolleys and units are extensively used in the hotel, restaurant and catering industry for maintaining food, which has been cooked, at an elevated temperature. In general, such chafing trolleys and units are located in restaurants and dining rooms of hotels for maintaining the cooked food at an elevated temperature prior to serving of the food. Such chafing trolleys and units typically comprise a plurality of food trays, generally of stainless steel, into which food to be maintained at an elevated temperature is located. The food trays are located in a water tray containing water which is maintained at an appropriate temperature for maintaining the food in the food trays at the desired elevated temperature. A heater shelf is located in such chafing trolleys and units below the water tray on which heaters are supported for heating the water in the water tray, for in turn maintaining the food in the food trays at the elevated temperature. In general, the spacing between the water tray and the heater shelf is relatively small, and in general, is suitable for accommodating wick based heaters which burn a liquid fuel, such as alcohol, or a canned chemical in a solid or gel form. A problem with such wick based heaters is that they generally burn at a fixed temperature, and it is not possible to vary the heat output, which in turn prevents easy regulation of the temperature of the water in the water tray, and in turn the elevated temperature at which the food is being maintained. This is undesirable.

A further disadvantage of such wick based heaters is that the liquid fuel is highly flammable, and can be easily spilt, thus leading to the possibility of fire and other safety problems. Additionally, such wick based heaters may include toxic chemicals or they may produce uneven flames and may also suffer from evaporation of toxic chemicals.

Attempts have been made to produce a gas powered heater which would be suitable for such chafing trolleys and units, however, such gas powered heaters suffer from a number of disadvantages. Firstly, the spacing between the heater shelf and the water tray is such that it is difficult to produce a gas powered heater of suitably low height to fit within the confined headroom between the heater shelf and the water tray. PCT published Specification No. WO 03/083368 discloses gas powered heaters for use in a chafing trolley. However, these heaters suffer from a number of disadvantages in that the fuel gas is stored in liquid form under pressure in a rechargeable reservoir. A serious problem with the gas powered heaters disclosed in this PCT specification is that the reservoir requires to be recharged at regular intervals, which is inconvenient, and is also hazardous. Typically, recharging of the reservoir of such gas powered heaters is carried out in a kitchen where there are exposed flames, and there is a serious risk of fire during recharging of the reservoir of the gas powered heaters disclosed in this specification.

Another gas powered heater which is provided for use with a chafing trolley or a chafing unit is disclosed in PCT published Specification No. WO 2008/119796. However, the gas powered heater disclosed in this PCT specification also has a rechargeable reservoir and thus suffers from similar problems as those of the gas powered heater of PCT Specification No. WO 03/083368.

Additionally, and of particular importance is that because of the construction of the gas powered heaters of both PCT Specification No. WO 03/083368 and WO 2008/119796, the overall height of the gas powered heaters is relatively large, and requires headroom, which is not always available in chafing trolleys and units between the heater shelf and the water tray.

There is therefore a need for a gas powered heater for use in a chafing trolley or unit which addresses at least some of the problems of known gas powered heaters.

The present invention is directed towards providing such a gas powered heater.

According to the invention there is provided a gas powered heater comprising a support element defining a hollow interior region and a downwardly facing open mouth providing access to the hollow interior region, the hollow interior region defining a canister accommodating location for accommodating a pressurised fuel gas canister therein in a substantially generally upright orientation, a coupling element located in the canister accommodating location of the hollow interior region secured to an upper portion of the support element, the coupling element being releasably engageable with an outlet port of a fuel gas canister for coupling the fuel gas canister to the support element in the canister accommodating location, a mounting platform formed in the support element, a fuel gas controller mounted on the mounting platform and extending downwardly therefrom into a valve accommodating location in the hollow interior region offset to one side of the canister accommodating location, the fuel gas controller being in communication with the coupling element through a fuel gas path for receiving fuel gas from the fuel gas canister through the coupling element, and a fuel gas burner element located externally of the support element above and substantially centrally aligned with the fuel gas controller, the fuel gas burner element communicating with the fuel gas controller for receiving fuel gas therefrom.

Preferably, the support element comprises a top wall, and the coupling element is mounted on the top wall and extends downwardly into the canister accommodating location therefrom.

Advantageously, the mounting platform is located at a level below the level of a portion of the top wall of the support element to which the coupling element is mounted.

In one aspect of the invention the mounting platform is located at a level of at least 5 mm below the level of the portion of the top wall of the support element to which the coupling element is mounted. Preferably, the mounting platform is located at a level of at least 7.5 mm below the level of the portion of the top wall of the support element to which the coupling element is mounted. Advantageously, the mounting platform is located at a level of at least 10 mm below the level of the portion of the top wall of the support element to which the coupling element is mounted.

In another aspect of the invention the mounting platform is spaced apart laterally from the coupling element. Preferably, the canister accommodating location defines a longitudinally extending main central axis which in use extends substantially vertically. Advantageously, the canister accommodating location is adapted for accommodating a fuel gas canister with a vertically extending central geometrical axis of the fuel gas canister substantially coinciding with the main central axis of the canister accommodating location.

In another aspect of the invention the valve accommodating location defines a longitudinally extending secondary central axis extending substantially parallel to the main central axis. Preferably, the fuel gas controller is located in the valve accommodating location with a longitudinally extending central axis of the fuel gas controller substantially coinciding with the secondary central axis of the valve accommodating location.

In one aspect of the invention the support element comprises a side wall extending around the hollow interior region. Preferably, the side wall defines the downwardly facing open mouth.

In another aspect of the invention the support element comprises an inclined wall extending around the top wall and inclining in a generally downwardly outwardly direction from the top wall. Preferably, a portion of the inclined wall terminates in the side wall of the support element. Advantageously, the inclined wall terminates in the mounting platform.

In another aspect of the invention a first portion of the side wall of the support element defines a portion of the canister accommodating location. Preferably, the first portion of the side wall of the support element defines at least 180° of the canister accommodating location. Advantageously, the first portion of the side wall is of part cylindrical shape defining the main central axis of the canister accommodating location.

In another aspect of the invention a second portion of the side wall of the support element defines a portion of the valve accommodating location. Preferably, the second portion of the side wall is of part cylindrical shape defining the secondary central axis of the valve accommodating location. Advantageously, the second portion of the side wall of the support element extends downwardly from the mounting platform.

In a further aspect of the invention a pair of spaced apart tangential side walls join the first and second cylindrical portions of the side wall.

In one aspect of the invention a carrier platform is mounted on the support element spaced apart above the mounting platform, and the fuel gas burner element is mounted on the carrier platform. Preferably, at least one pillar extending upwardly from the mounting platform supports the carrier platform above the mounting platform. Advantageously, the fuel gas burner element is mounted on the carrier platform with an inlet port thereof facing downwardly and being aligned with an upwardly facing outlet port of the fuel gas controller extending from the mounting platform for receiving fuel gas from the fuel gas controller.

In one embodiment of the invention the inlet port to the fuel gas burner is spaced apart above the outlet port from the fuel gas controller to define an annular gap therebetween to in turn form a venturi mixer for mixing fuel gas being delivered to the fuel gas burner with air.

In one aspect of the invention the outlet port of the fuel gas controller comprises an outlet jet through which fuel gas is delivered from the outlet port.

Preferably, the fuel gas burner element and the fuel gas controller are in substantial vertical alignment with each other.

In another aspect of the invention the fuel gas controller comprises a fuel gas control valve operable between a closed state isolating the fuel gas burner from the fuel gas supply, and a fully open state for delivering fuel gas to the fuel gas burner. Preferably, the fuel gas control valve is operable in a plurality of open states between the closed state and the fully open state for controlling the rate at which fuel gas is supplied to the fuel gas burner.

In one aspect of the invention a control lever is operably coupled to the fuel gas control valve for facilitating manual operation of the fuel gas control valve between the closed state and the fully open state.

In another aspect of the invention the fuel gas burner element comprises a housing having a gas catalytic combustion element located therein for converting fuel gas to heat by a catalytic reaction.

Preferably, the gas catalytic combustion element is adapted to permit slippage of fuel gas therethrough, so that the fuel gas is burnt in a flame downstream of the catalytic combustion element.

Advantageously, the housing of the burner element defines an upwardly facing open mouth, and the gas catalytic combustion element is located in the housing adjacent the open mouth thereof.

In one embodiment of the invention a diffuser element is located in the housing of the fuel gas burner element upstream of the catalytic combustion element, and downstream of the inlet port to the fuel gas burner element. Preferably, the diffuser element is spaced apart from the gas catalytic combustion element.

In one aspect of the invention the gas catalytic combustion element is spaced apart above the diffuser element.

In another aspect of the invention the diffuser element comprises a central blank portion on which fuel gas from the inlet port of the fuel gas burner element impinges. Preferably, a plurality of perforations extend through the diffuser element offset from the central blank portion for accommodating fuel gas therethrough to the catalytic combustion element. Advantageously, the perforations extending through the diffuser element are located at spaced apart intervals around the central blank portion thereof.

In another aspect of the invention the diffuser element comprises a planar plate member.

In another aspect of the invention the planar plate member of the diffuser element substantially defines the cross-section of the housing of the fuel gas burner element.

In one embodiment of the invention the support element is adapted to accommodate a fuel gas canister in the fuel gas accommodating location with a portion of the fuel gas canister extending downwardly from the canister accommodating location through the downwardly facing open mouth, so that the fuel gas canister acts as a stand for the gas powered heater.

In another embodiment of the invention the depth of the side wall of the support element is such that a standard fuel gas canister extends downwardly from the canister accommodating location through the downwardly facing open mouth of the support element.

In a further embodiment of the invention the support element is adapted to accommodate a fuel gas canister in the canister accommodating location with the fuel gas canister located entirely within the support element.

In a still further embodiment of the invention a fuel gas canister of pressurised fuel gas in liquid form is located in the canister accommodating location coupled to the support element by the coupling element. Preferably, the fuel gas canister comprises a disposable pressurised fuel gas canister.

In another embodiment of the invention the gas powered heater with the fuel gas canister located in the canister accommodating location of the support element and coupled thereto by the coupling element is of overall height in the range of 50 mm to 150 mm. Preferably, the gas powered heater with the fuel gas canister located in the canister accommodating location of the support element and coupled thereto by the coupling element is of overall height which does not exceed 100 mm. Advantageously, the gas powered heater with the fuel gas canister located in the canister accommodating location of the support element and coupled thereto by the coupling element is of overall height of approximately 83 mm.

In another embodiment of the invention the support element is adapted to accommodate a pressurised fuel gas canister of diameter not more than 100 mm and of overall height not more than 70 mm.

Preferably, the support element is adapted for receiving a pressurised fuel gas canister of diameter of approximately 90 mm and of overall height of approximately 64 mm.

The advantages of the invention are many. A particularly important advantage of the invention is that the headroom required by the gas powered heater according to the invention is relatively low. This advantage is largely achieved by virtue of the fact that the fuel gas controller and the fuel gas burner element are located by the support element offset to one side of the canister accommodating location, and thereby the overall height of the gas powered heater including the pressurised fuel gas canister is significantly lower than those known heretofore, and thus the gas powered heater according to the invention can operate with significantly less headroom than gas powered heaters known heretofore. Additionally, by virtue of the fact that the fuel gas controller and the fuel gas burner element are offset to one side of the canister accommodating location, the canister accommodating location can accommodate a fuel gas canister of height greater than fuel gas canisters known heretofore, and still maintain a relatively low overall height of the heater. A particularly important advantage achieved by this aspect of the invention is that the gas powered heater can be used with a standard pressurised disposable fuel gas canister, and thus, there is no need for the gas powered heater according to the invention to be provided with a rechargeable reservoir.

The invention will be more clearly understood from the following description of some preferred embodiments thereof, which are given by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a gas powered heater according to the invention illustrated in use,

FIG. 2 is a cross-sectional side elevational view of the gas powered heater of FIG. 1 illustrated in use,

FIG. 3 is a top plan view of a portion of the gas powered heater of FIG. 1,

FIG. 4 is a cross-sectional side elevational view of the portion of the gas powered heater of FIG. 3 on the line IV-IV of FIG. 3,

FIG. 5 is an enlarged cross-sectional side elevational view of a detail of the gas powered heater of FIG. 1,

FIG. 6 is a top plan view of a detail of the gas powered heater of FIG. 1,

FIG. 7 is a cross-sectional side elevational view of the detail of FIG. 6 of the gas powered heater of FIG. 1 on the line VII-VII of FIG. 6,

FIG. 8 is a perspective view of another detail of the gas powered heater of FIG. 1,

FIG. 9 is a perspective view of a gas powered heater according to another embodiment of the invention, and

FIG. 10 is a perspective view of a gas powered heater according to a further embodiment of the invention.

Referring to the drawings, and initially to FIGS. 1 to 8 thereof, there is illustrated a gas powered heater according to the invention, indicated generally by the reference numeral 1. The gas powered heater 1 is particularly suitable for use in a chafing trolley or a chafing unit for maintaining cooked food at an elevated temperature, and is particularly suitable, as will be described in more detail below, for use in a chafing trolley or a chafing unit of the type which is suitable for use with gel burners. The gas powered heater 1 in this embodiment of the invention is adapted for use with a disposable proprietary pressurised fuel gas canister 3, which is of the type in which fuel gas is supplied in liquid form under pressure. The fuel gas canister 3 is of the type which is typically referred to as a gas cartridge, and is of capacity of 100 grams and comprises a base 4, a cylindrical side wall 5 which extends upwardly from the base 4, and a top wall 6 which inclines upwardly inwardly from the side wall 5 to an upwardly facing connector 8 within which an outlet port is located. The diameter d of the side wall 5 is approximately 90 mm, while the overall height h of the canister 3 from the base 4 to the top of the connector 8 is approximately 64 mm, see FIG. 2.

Turning now to the gas powered heater 1, the gas powered heater 1 comprises a support element 10 of stainless steel and of inverted dish shape which defines a hollow interior region 12 and a downwardly facing open mouth 14 to the hollow interior region 12. The fuel gas canister 3 is located in the hollow interior region 12 as will be described below, and extends downwardly from the hollow interior region 12 through the open mouth 14, and as well as providing a supply of fuel gas to the gas powered heater 1, the fuel gas canister 3 also acts as a stand on which the fuel gas heater 1 stands in use. A coupling element 15 located in the hollow interior region 12 and secured to the support element 10 releasably engages and secures the fuel gas canister 3 in the hollow interior region 12 of the support element 10. Fuel gas is supplied from the fuel gas canister 3 as will be described in detail below through a fuel gas controller 17 to a fuel gas burner element 18 where the fuel gas is converted to heat by a gas catalytic combustion element 20. The gas catalytic combustion element 20 permits slippage of fuel gas therethrough so that some of the fuel gas is burnt in a flame by the burner element 18.

Turning initially to the support element 10, the support element 10 comprises a top wall 22 and a side wall 23 which extends around the hollow interior region 12. An inclined wall 25 extending around the top wall 22 inclines in a generally outwardly downwardly direction towards a first portion 27 of the side wall 23. A mounting platform 28 is formed in the support element 10 which extends inwardly from a second portion 29 of the side wall 23 to the inclined wall 25. The mounting platform 28 is provided for mounting the fuel gas controller 17 in the hollow interior region 12 of the support element 10 as will be described below. A pair of spaced apart tangential walls 30 extend between the first and second portions 27 and 29 of the side wall 23 on respective opposite sides of the support element 10.

The support element 10 defines a canister accommodating location 33 in the hollow interior region 12 for accommodating the fuel gas canister 3 in the support element 10. The canister accommodating location 33 is partly defined by the first portion 27 of the side wall 23 which is of part cylindrical shape. The part cylindrical first portion 27 of the side wall 23 defines a geometrical central axis which defines a longitudinally extending main central axis 34 of the canister accommodating location 33, which in use extends substantially vertically. The coupling element 15 couples and locates the fuel gas canister 3 in the canister accommodating location 33 with a vertically extending central geometrical axis of the fuel gas canister 3 substantially coinciding with the main central axis 34 of the canister accommodating location 33.

The support element 10 also defines a valve accommodating location 35 in the hollow interior region 12 which is offset to one side of the canister accommodating location 33 for accommodating the fuel gas controller 17 spaced apart laterally from the coupling element 15, and in turn laterally spaced apart from the fuel gas canister 3. The second portion 29 of the side wall 23 is of part cylindrical shape and defines a portion of the valve accommodating location 35. The second portion 29 of the side wall 23 defines a geometrical axis which defines a longitudinally extending secondary central axis 36 of the valve accommodating location 35. The secondary central axis 36 extends parallel to the main central axis 34 of the canister accommodating location 33, and in use extends substantially vertically. A flange 39 extending outwardly and around the side wall 23 reinforces the side wall 23, and in turn the support element 10.

The coupling element 15 is secured to the top wall 22 in the hollow interior region 12 of the support element 10 and is centrally located in the canister accommodating location 33 on the main central axis 34 for releasably engaging the connector 8 of the fuel gas canister 3 with the fuel gas canister 3 located in the canister accommodating location 33 with the central geometrical axis of the fuel gas canister 3 coinciding with the main central axis 34 of the canister accommodating location 33. A release pin 40 located in the coupling element 15 and extending downwardly therein is provided for engaging and opening a valve (not shown) in the outlet port (also not shown) in the connector 8 of the fuel gas canister 3. Such outlet ports in a connector of such a fuel gas canister 3 will be well known to those skilled in the art. A fuel gas supply pipe 42 which is coupled to the coupling element 15 forms a fuel gas path through which fuel gas is supplied from the fuel gas canister 3 to a fuel gas inlet port 43 of the fuel gas controller 17.

The fuel gas controller 17 comprises a controller housing 44 within which a control valve 45 is housed. Fuel gas is supplied to the control valve 45 from the fuel gas inlet port 43 as will be described below. The control valve 45 comprises a threaded housing 46 which is screwed into the controller housing 44 of the fuel gas controller 17. A threaded portion 47 of the housing 46 of the control valve 45 extends through an opening 48 in the mounting platform 28. A nut 49 threaded onto the threaded portion 47 of the housing 46 of the control valve 45 secures the control valve 45 in the mounting platform 28, and in turn secures the controller housing 44 of the fuel gas controller 17 in the mounting platform 28. The opening 48 in the mounting platform 28 is located so that the fuel gas controller 17 is located with a longitudinally extending central axis of the fuel gas controller 17 substantially coinciding with the secondary central axis 36 of the valve accommodating location 35. Thereby the fuel gas controller 17 is centrally located in the valve accommodating location 35.

With the fuel gas controller 17 so mounted on the mounting platform 28 and extending downwardly into the valve accommodating location 35, the fuel gas controller 17 is located in the hollow interior region 12 of the support element 10 spaced apart from and to one side of the fuel gas canister 3.

The control valve 45 is operable between a closed state with the fuel gas from the fuel gas canister 3 isolated from the fuel gas burner element 18, and a fully open state with fuel gas from the fuel gas canister 3 supplied to the fuel gas burner element 18. Additionally, the control valve 45 is operable in a plurality of intermediate open states between the closed state and the fully open state for controlling the flow rate of fuel gas from the fuel gas canister 3 to the fuel gas burner element 18. A manually operable lever 50 extending radially from the control valve 45 is operable through an arc in the direction of the arrows A and B for operating the control valve 45 between the closed state and the fully open state.

An outlet port 51 from the control valve 45 is located in the threaded portion 47 of the housing 46 and comprises an outlet jet 57 which directs fuel gas directly upwardly therefrom to the fuel gas burner element 18 as will be described below.

The pipe 42 is coupled to the fuel gas inlet port 43 of the controller housing 44 for delivering fuel gas through the controller housing 44 to the control valve 45. An emergency shut-off valve 52 is formed in the controller housing 44 between the control valve 45 and the fuel gas inlet port 43 for isolating the fuel gas burner element 18 from the fuel gas canister 3 in the event of the heater 1 toppling over. The emergency shut-off valve 52 comprises a ball 53 located in a valve chamber 54 formed in the controller housing 44. The ball 53 is rollable in the valve chamber 54 from an open state with the ball 53 resting on an end wall 55 of the controller housing 44 while the gas powered heater 1 is in a normal upright operating state, to a shut-off state with the ball 53 closing an inlet port 56 to the control valve 45 from the valve chamber 54 in the event of the gas powered heater 1 toppling over. In the open state of the ball 53, the inlet port 56 to the control valve 45 communicates with the fuel gas inlet port 43 through the valve chamber 54. In the shut-off state of the ball 53, the ball 53 isolates the inlet port 56 to the control valve 45 from the fuel gas inlet port 43.

A pair of spaced apart pillars 58 extending upwardly from the mounting platform 28 support a carrier platform 60 of stainless steel spaced apart above the mounting platform 28. Nuts 61 on the pillars 58 secure the carrier platform 60 to the pillars 58. In this embodiment of the invention the carrier platform 60 is located at a level relative to the level of the top wall 22 of the support element 10, so that top surfaces of the carrier platform 60 and the top wall 22 substantially define a common plane.

The fuel gas burner element 18 comprises a burner housing 62 of circular transverse cross-section which is mounted on the carrier platform 60 and extends upwardly therefrom. The burner housing 62 defines a geometrical central axis, and is mounted on the carrier platform 60 with its geometrical central axis substantially coinciding with the secondary central axis 36 of the valve accommodating location 35, as will be described below. An opening 63 in the carrier platform 60 accommodates a threaded spigot 64 extending downwardly from the burner housing 62. A nut 65 on the threaded spigot 64 clamps and secures the burner housing 62 on the carrier platform 60. An inlet port 66 extends through the spigot 64 into a burner chamber 68 of the burner housing 62 for accommodating fuel gas from the outlet jet 57 in the outlet port 51 of the control valve 45 to the burner chamber 68. The opening 63 in the carrier platform 60 defines a geometrical central axis which substantially coincides with the secondary central axis 36, so that the opening 63 is vertically aligned with the opening 48 in the mounting platform 28, so that in turn the fuel gas burner element 18 is vertically aligned with and above the fuel gas controller 17, and the inlet port 66 is in turn vertically aligned with the outlet jet 57 in the outlet port 51 of the control valve 45. Thus, the geometrical central axis of the burner housing 62 substantially coincides with the secondary central axis 36 of the valve accommodating location 35.

The burner housing 62 terminates in an upwardly facing open mouth 70. The gas catalytic combustion element 20 is located in the burner chamber 68 adjacent the open mouth 70. A diffuser element 72 which is formed by a planar plate member 73, see FIG. 8, is located in the burner chamber 68 below and upstream of the diffuser element 72, and is supported on a tapering portion 71 of the burner housing 62, see FIG. 5. The plate member 73 of the diffuser element 72 is of substantially circular shape and defines the transverse cross-section of the burner chamber 68 adjacent the open mouth 70. The diffuser element 72 comprises upwardly extending support members 74 located around the periphery thereof on which the gas catalytic combustion element 20 is supported. A central portion 75 of the diffuser plate member 73 is blank so that fuel gas impinging on the central blank portion 75 from the inlet port 66 is diffused by the central blank portion 75. A plurality of perforations 76 extend through the plate member 73 of the diffuser element 72 around the central blank portion 75 for accommodating fuel gas therethrough to the gas catalytic combustion element 20. Additionally, a plurality of recesses 78 formed in the periphery of the plate member 73 between the support members 74 also accommodate fuel gas which has been diffused by the central blank portion 75 to the gas catalytic combustion element 20.

The gas catalytic combustion element 20 is of circular shape substantially defining the transverse cross-section of the burner chamber 68 adjacent the open mouth 70, and comprises a ceramics based element coated with a precious metal. A plurality of perforations 80 extend through the gas catalytic combustion element 20 for accommodating fuel gas therethrough, see FIGS. 6 and 7. The gas catalytic combustion element 20 is adapted to convert fuel gas to heat, and at the same time permit slippage of fuel gas through the perforations 80, so that some of the fuel gas burns with a flame downstream of the gas catalytic combustion element in the open mouth 70 of the burner housing 62.

The carrier platform 60 is spaced apart above the mounting platform 28, so that an annular gap 82 is formed extending around the outlet port 51 of the control valve 45 and the inlet port 66 to the fuel gas burner element 18 in order to form a venturi mixer through which air is drawn into and mixed with the fuel gas stream issuing from the outlet jet 57 in the outlet port 51 of the control valve 45 and delivered as a fuel gas/air mixture into the inlet port 66 of the fuel gas burner element 18.

In this embodiment of the invention the mounting platform 28 is located at a level spaced apart a distance L of approximately 10 mm below the level of the top wall 22 of the support element 10 adjacent the location at which the coupling element 15 is located in the top wall 22, see FIG. 2. By locating the mounting platform 28 at the level spaced apart the distance L of 10 mm below the level of the top wall 22, the headroom required by the fuel gas burner element 18 is minimised, thereby minimising the overall headroom required by the gas powered heater 1.

In use, a suitable proprietary disposable fuel gas canister 3 is coupled to the support element 10 by entering the fuel gas canister 3 through the downwardly facing open mouth 14, and with the fuel gas canister 3 located in the canister accommodating location 33 engaging the connector 8 of the fuel gas canister 3 with the coupling element 15 of the support element 10. With a lower portion of the fuel gas canister 3 extending downwardly through the open mouth 14 and acting as a stand for the gas powered heater 1, the gas powered heater 1 is ready for use. When it is desired to use the gas powered heater 1, the lever 50 is operated for operating the control valve 45 from the closed state to the fully open state, and fuel gas is delivered from the fuel gas canister 3 to the fuel gas burner element 18. The fuel gas/air mixture exiting through the gas catalytic combustion element 20 is ignited by a flame or other suitable means, for example, a spark or the like, to commence burning in a flame. The root of the flame in turn heats the gas catalytic combustion element 20 to its ignition temperature, which in turn commences to convert fuel gas/air mixture to heat by catalytic reaction. However, the gas catalytic combustion element 20 allows slippage of the fuel gas/air mixture therethrough, so that some of the fuel gas/air mixture continues to burn in a flame downstream of the gas catalytic combustion element 20, in other words, above the gas catalytic combustion element 20. The gas powered heater 1 is then placed on a heater shelf of a chafing trolley or unit to maintain cooked food at an elevated temperature. The heat output of the gas powered heater 1 is varied by controlling the rate of flow of the fuel gas through the control valve 45 by appropriately setting the lever 50 at an appropriate position between the closed state and the fully open state of the control valve 45.

When the fuel gas powered heater 1 is no longer required, the lever 50 is operated for operating the control valve 45 into the closed state.

On the fuel gas canister 3 becoming exhausted, the fuel gas canister 3 is disengaged from the support element 10 by disengaging the connector 8 of the fuel gas canister 3 from the coupling element 15. Thereafter, a new fuel gas canister 3 is connected to the support element by connecting the connector 8 of the new fuel gas canister 3 into the coupling element 15 with the fuel gas canister 3 located in the canister accommodating location 33.

By virtue of the fact that the fuel gas controller 17 is located to one side of and spaced apart from the fuel gas canister 3, the overall height of the gas powered heater element 1 is minimised, and thus, the headroom required by the gas powered heater 1 is likewise minimised.

In this embodiment of the invention the support element 10 is adapted for use with a proprietary disposable cylindrical fuel gas canister 3 of total height h of approximately 64 mm, and diameter d of approximately 90 mm. With the fuel gas canister 3 coupled to the coupling element 15 of the support element 10, the overall height Hof the gas powered heater from the base 4 of the fuel gas canister 3 to a top peripheral edge 83 of the burner housing 62 is approximately 86 mm. A gas powered heater of such a height as the height H of 86 mm approximately can be accommodated within the headroom available in most chafing trolleys and units.

Typically, the spacing between the heater shelf of typical chafing trolleys and chafing units and the water tray above the heater element is in the range of 105 mm to 130 mm, thus providing a clearance of between 20 mm and 45 mm between the top peripheral edge 83 of the fuel gas burner element 18 and the underside of the water tray when the gas powered heater 1 with the fuel gas canister 3 assembled thereto is located on the heater shelf of such chafing trolleys and units. Accordingly, the gas powered heater according to the present invention is suitable for use with such chafing trolleys and units.

Referring now to FIG. 9, there is illustrated a gas powered heater according to another embodiment of the invention, indicated generally by the reference numeral 90, which is also suitable for use with a chafing trolley or a chafing unit. The gas powered heater 90 is substantially similar to the gas powered heater 1 described with reference to FIGS. 1 to 8, and similar components are identified by the same reference numerals. The only difference between the gas powered heater 90 and the gas powered heater 1 is in the depth of the side wall 23 of the support element 10. In this embodiment of the invention the side wall 23 is of overall height such that the side wall 23 extends downwardly and terminates in a lower engagement portion 91 which is adapted to engage the heater shelf of the chafing trolley or chafing unit and thus act as a stand for the support element 10. In this embodiment of the invention the fuel gas canister 3 is located entirely within the hollow interior region 12 defined by the support element 10 and does not engage the heater shelf of the chafing trolley or chafing unit. Otherwise, the gas powered heater 90 and its use is similar to the gas powered heater 1.

Referring to FIG. 10, there is illustrated a gas powered heater according to a further embodiment of the invention, indicated generally by the reference numeral 95, which is also suitable for use with a chafing trolley or a chafing unit. The gas powered heater 95 is substantially similar to the gas powered heater 1 described with reference to FIGS. 1 to 8, and similar components are identified by the same reference numerals. The only difference between the gas powered heater 95 and the gas powered heater 1 is that the carrier platform 60 is located at a level slightly above the level of the top wall 22 of the support element 10. The top surface of the carrier platform 60 is at a level above the level of the top surface of the top wall 22 of the support element 10 which corresponds to the thickness of the stainless steel sheet material of the carrier platform 60, which in this embodiment of the invention is approximately 0.5 mm. Accordingly, in this embodiment of the invention the height of the carrier platform 60 above the mounting platform 28 is approximately 10.5 mm.

Otherwise, the gas powered heater 95 according to this embodiment of the invention is similar to the gas powered heater 1 described with reference to FIGS. 1 to 8, as is its use likewise similar to the use of the gas powered heater 1 described with reference to FIGS. 1 to 8.

While the gas powered heaters according to the invention have been described as comprising a support element of a particular material, the support element may be of any other suitable material, whether a metal material, a plastics material or otherwise. Additionally, it is envisaged that while it is desirable, it is not necessary that the support element need be dish-shaped. In certain cases, it is envisaged that the side wall of the support element may be omitted.

While the gas powered heaters have been described for use in a chafing trolley or a chafing unit, it will be appreciated that the gas powered heaters may be used in many other applications both in the catering and hospitality industries and in other industries, and it will also be appreciated that the gas powered heaters may be used as a standalone heater or stove.

While the gas powered heaters according to the invention have been described for use with a disposable cylindrical gas canister of total height of approximately 64 mm and diameter of approximately 90 mm, it is envisaged that the gas powered heaters may be adapted for use with disposable gas canisters of total height and diameter other than 64 mm in height and 90 mm in diameter. Indeed, it is envisaged that the gas powered heaters may be adapted for use with disposable cylindrical fuel gas canisters of diameter up to 100 mm, and total height of up to 70 mm. Indeed, it will be appreciated that while the gas powered heaters have been described as being adapted for use with a disposable cylindrical fuel gas canister, the gas powered heaters could be adapted for use with disposable fuel gas canisters of other shapes besides cylindrical, for example, square, polygonal, for example, hexagonal, octagonal or any other suitable or desirable shapes.

It will also be appreciated that while the gas powered heaters according to the invention have been described as having an overall height of approximately 83 mm, it is envisaged that the gas powered heaters according to the invention when coupled to a disposable fuel gas canister could be provided with a total overall height in the range of 50 mm to 150 mm, but in general, it is envisaged that the overall height of the gas powered heaters including the disposable fuel gas canister would not exceed 100 mm.

Additionally, it is envisaged that while the vertical spacing between the level of the mounting platform 28 and the level of the top wall 22 of the support element 10 has been described as being approximately 10 mm, it is envisaged that the vertical spacing between the levels of the mounting platform 28 and the top wall 22 could be as high as 20 mm, where the mounting platform 28 would be located at a level 20 mm below the level of the top wall 22 of the support element 10. It is also envisaged that in certain cases, the mounting platform may be spaced at a level below the level of the top wall 22 of the support element 10 of as little as 5 mm.

It is also envisaged that the gas catalytic combustion element, instead of being a ceramics based gas catalytic combustion element, may comprise a wire mesh gas catalytic combustion element, or a fibre based gas catalytic combustion element, in which case, the wires or the fibres, as the case may be, would be coated with an appropriate precious metal.

While the fuel gas burner element has been described as comprising a burner housing of circular transverse cross-section, the transverse cross-section of the burner housing of the fuel gas burner element may be of any desired cross-section. 

1-53. (canceled)
 54. A gas powered heater comprising a support element defining a hollow interior region and a downwardly facing open mouth providing access to the hollow interior region, the hollow interior region defining a canister accommodating location for accommodating a pressurised fuel gas canister therein in a substantially generally upright orientation, a coupling element located in the canister accommodating location of the hollow interior region secured to an upper portion of the support element, the coupling element being releasably engageable with an outlet port of a fuel gas canister for coupling the fuel gas canister to the support element in the canister accommodating location, a mounting platform formed in the support element, a fuel gas controller mounted on the mounting platform and extending downwardly therefrom into a valve accommodating location in the hollow interior region offset to one side of the canister accommodating location, the fuel gas controller being in communication with the coupling element through a fuel gas path for receiving fuel gas from the fuel gas canister through the coupling element, and a fuel gas burner element located externally of the support element above and substantially centrally aligned with the fuel gas controller, the fuel gas burner element communicating with the fuel gas controller for receiving fuel gas therefrom.
 55. A gas powered heater as claimed in claim 54 in which the support element comprises a top wall, and the coupling element is mounted on the top wall and extends downwardly into the canister accommodating location therefrom, and advantageously, the mounting platform is located at a level below the level of a portion of the top wall of the support element to which the coupling element is mounted, and preferably, the mounting platform is located at a level of at least 5 mm below the level of the portion of the top wall of the support element to which the coupling element is mounted, and advantageously, the mounting platform is located at a level of at least 7.5 mm below the level of the portion of the top wall of the support element to which the coupling element is mounted, and preferably, the mounting platform is located at a level of at least 10 mm below the level of the portion of the top wall of the support element to which the coupling element is mounted.
 56. A gas powered heater as claimed in claim 54 in which the mounting platform is spaced apart laterally from the coupling element, and advantageously, the canister accommodating location defines a longitudinally extending main central axis which in use extends substantially vertically, and preferably, the canister accommodating location is adapted for accommodating a fuel gas canister with a vertically extending central geometrical axis of the fuel gas canister substantially coinciding with the main central axis of the canister accommodating location, and advantageously, the valve accommodating location defines a longitudinally extending secondary central axis extending substantially parallel to the main central axis, and preferably, the fuel gas controller is located in the valve accommodating location with a longitudinally extending central axis of the fuel gas controller substantially coinciding with the secondary central axis of the valve accommodating location.
 57. A gas powered heater as claimed in claim 56 in which the support element comprises a side wall extending around the hollow interior region, and preferably, the side wall defines the downwardly facing open mouth.
 58. A gas powered heater as claimed in claim 57 in which the support element comprises an inclined wall extending around the top wall and inclining in a generally downwardly outwardly direction from the top wall, and preferably, a portion of the inclined wall terminates in the side wall of the support element.
 59. A gas powered heater as claimed in claim 58 in which the inclined wall terminates in the mounting platform.
 60. A gas powered heater as claimed in claim 57 in which a first portion of the side wall of the support element defines a portion of the canister accommodating location, and preferably, the first portion of the side wall of the support element defines at least 180° of the canister accommodating location, and advantageously, the first portion of the side wall is of part cylindrical shape defining the main central axis of the canister accommodating location.
 61. A gas powered heater as claimed in claim 60 in which a second portion of the side wall of the support element defines a portion of the valve accommodating location, and preferably, the second portion of the side wall is of part cylindrical shape defining the secondary central axis of the valve accommodating location, and advantageously, the second portion of the side wall of the support element extends downwardly from the mounting platform, and preferably, a pair of spaced apart tangential side walls join the first and second cylindrical portions of the side wall.
 62. A gas powered heater as claimed in claim 54 in which a carrier platform is mounted on the support element spaced apart above the mounting platform, and the fuel gas burner element is mounted on the carrier platform, and preferably, at least one pillar extending upwardly from the mounting platform supports the carrier platform above the mounting platform, and advantageously, the fuel gas burner element is mounted on the carrier platform with an inlet port thereof facing downwardly and being aligned with an upwardly facing outlet port of the fuel gas controller extending from the mounting platform for receiving fuel gas from the fuel gas controller, and preferably, the inlet port to the fuel gas burner is spaced apart above the outlet port from the fuel gas controller to define an annular gap therebetween to in turn form a venturi mixer for mixing fuel gas being delivered to the fuel gas burner with air, and advantageously, the outlet port of the fuel gas controller comprises an outlet jet through which fuel gas is delivered from the outlet port.
 63. A gas powered heater as claimed in claim 54 in which the fuel gas burner element and the fuel gas controller are in substantial vertical alignment with each other, and preferably, the fuel gas controller comprises a fuel gas control valve operable between a closed state isolating the fuel gas burner from the fuel gas supply, and a fully open state for delivering fuel gas to the fuel gas burner, and preferably, the fuel gas control valve is operable in a plurality of open states between the closed state and the fully open state for controlling the rate at which fuel gas is supplied to the fuel gas burner, and advantageously, a control lever is operably coupled to the fuel gas control valve for facilitating manual operation of the fuel gas control valve between the closed state and the fully open state.
 64. A gas powered heater as claimed in claim 54 in which the fuel gas burner element comprises a housing having a gas catalytic combustion element located therein for converting fuel gas to heat by a catalytic reaction, and preferably, the gas catalytic combustion element is adapted to permit slippage of fuel gas therethrough, so that the fuel gas is burnt in a flame downstream of the catalytic combustion element, and advantageously, the housing of the burner element defines an upwardly facing open mouth, and the gas catalytic combustion element is located in the housing adjacent the open mouth thereof, and preferably, a diffuser element is located in the housing of the fuel gas burner element upstream of the catalytic combustion element, and downstream of the inlet port of the fuel gas burner element.
 65. A gas powered heater as claimed in claim 64 in which the diffuser element is spaced apart from the gas catalytic combustion element.
 66. A gas powered heater as claimed in claim 64 in which the gas catalytic combustion element is spaced apart above the diffuser element.
 67. A gas powered heater as claimed in claim 64 in which the diffuser element comprises a central blank portion on which fuel gas from the inlet port of the fuel gas burner element impinges.
 68. A gas powered heater as claimed in claim 67 in which a plurality of perforations extend through the diffuser element offset from the central blank portion for accommodating fuel gas therethrough to the catalytic combustion element, and preferably, the perforations extending through the diffuser element are located at spaced apart intervals around the central blank portion thereof.
 69. A gas powered heater as claimed in claim 64 in which the diffuser element comprises a planar plate member, and preferably, the planar plate member of the diffuser element substantially defines the cross-section of the housing of the fuel gas burner element.
 70. A gas powered heater as claimed in claim 54 in which the support element is adapted to accommodate a fuel gas canister in the fuel gas accommodating location with a portion of the fuel gas canister extending downwardly from the canister accommodating location through the downwardly facing open mouth, so that the fuel gas canister acts as a stand for the gas powered heater, and preferably, the depth of the side wall of the support element is such that a standard fuel gas canister extends downwardly from the canister accommodating location through the downwardly facing open mouth of the support element.
 71. A gas powered heater as claimed in claim 54 in which the support element is adapted to accommodate a fuel gas canister in the canister accommodating location with the fuel gas canister located entirely within the support element.
 72. A gas powered heater as claimed in claim 54 in which a fuel gas canister of pressurised fuel gas in liquid form is located in the canister accommodating location coupled to the support element by the coupling element, and preferably, the fuel gas canister comprises a disposable pressurised fuel gas canister.
 73. A gas powered heater as claimed in claim 72 in which the gas powered heater with the fuel gas canister located in the canister accommodating location of the support element and coupled thereto by the coupling element is of overall height in the range of 50 mm to 150 mm, and preferably, the gas powered heater with the fuel gas canister located in the canister accommodating location of the support element and coupled thereto by the coupling element is of overall height which does not exceed 100 mm, and advantageously, the gas powered heater with the fuel gas canister located in the canister accommodating location of the support element and coupled thereto by the coupling element is of overall height of approximately 83 mm, and advantageously, the support element is adapted to accommodate a pressurised fuel gas canister of diameter not more than 100 mm and of overall height not more than 70 mm, and preferably, the support element is adapted for receiving a pressurised fuel gas canister of diameter of approximately 90 mm and of overall height of approximately 64 mm. 